''Ivesia callida'' is a rare species of flowering plant, in the

rose family Rosaceae (), the rose family, is a medium-sized family of flowering plants that includes 4,828 known species in 91 genera. The name is derived from the type genus ''Rosa''. Among the most species-rich genera are '' Alchemilla'' (270), ''Sorbus ...

, known by the common name Tahquitz mousetail. It is a small perennial herb which forms matted patches of hanging foliage on cliff faces. The leaves are strips of oval-shaped green leaflets. Each leaf is up to 7 centimeters long and has several pairs of hairy, glandular leaflets. The thin, green, hanging stems grow up to 15 centimeters long and bear an

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

of several flowers. Each flower has five hairy, pointed

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coined b ...

s and five round to oval white petals. The center of the flower contains twenty

stamen The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filame ...

s with disc-shaped anthers and several

pistils Gynoecium (; ) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ''pistils'' ...

. The plant is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the

San Jacinto Mountains The San Jacinto Mountains (''Avii Hanupach''Munro, P., et al. ''A Mojave Dictionary''. Los Angeles: UCLA. 1992. in Mojave) are a mountain range in Riverside County, located east of Los Angeles in southern California in the United States. The mou ...

Riverside County, California Riverside County is a County (United States), county located in the southern California, southern portion of the U.S. state of California. As of the 2020 United States Census, 2020 census, the population was 2,418,185, making it the fourth-most ...

, where it is known from only two occurrences. The plant grows in cracks and crevices of

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

mountain cliffs. It was named for

Tahquitz Rock Tahquitz Peak (pronounced , sometimes ) is a granite, rock formation located on the high western slope of the San Jacinto mountain range in Riverside County, Southern California, United States, above the mountain town of Idyllwild. Tahquitz ha ...

, a rock formation in its endemic range. The rock formation was named for the Native American spirit Tahquitz.

External links

Jepson Manual Treatment: ''Ivesia callida''''Ivesia callida'' — U.C. Photo gallery
callida Endemic flora of California Flora of Riverside County, California Natural history of the Peninsular Ranges Flora and fauna of the San Jacinto Mountains Critically endangered flora of California {{Rosaceae-stub